Racial disparities in cancer treatment are well described but poorly understood. Although most experts believe that access to care contributes to these disparities, access for vulnerable populations is a complex, multidimensional process that is inadequately captured by measures of insurance coverage or travel time. In this application, we propose to build upon our prior researching racial disparities, prostate cancer treatment and access to care to investigate the contribution of a multidimensional picture of health care access to racial differences in prostate cancer treatment. We will collect primary data on a population based sample of men diagnosed with localized prostate cancer (N=3,000) in 8 counties in the Greater Philadelphia area and on the urologists and radiation oncologists who form their access to prostate cancer treatment. We will focus on this area as it is the primary focus of the proposed center and because the multiple dimensions of cancer care in urban populations are poorly understood. Building on the access framework of Penchansky and Thomas, we will assess the accessibility /availability, accommodation, affordability, & acceptability of prostate cancer care, using data from a patient survey, administrative records, & a provider inventory. Following the framework of Aday & Andersen, we will create spatial measures of potential access & individual measures of experienced access (a form of realized access). We will incorporate information about the characteristics of providers using data from patients about their experiences, as well as data from the AMA masterfile about provider board certification and training. We will then examine the relationships between potential access, experienced access, & differences in treatment as well as the degree to which these effects are mediated by insurance coverage, socioeconomic status & neighborhood deprivation. To our knowledge, this will be the first study to construct a comprehensive, multi-dimensional picture of access to cancer care by collecting information from patients, providers & administrative sources & to use this picture to improve our understanding of a racial difference in cancer treatment.